Electromechanical fluidic transducer

ABSTRACT

AN ELECTROMECHANICAL FLUIDIC TRANSDUCER HAS A FLOW FEED LINE COMMUNICATING WITH TWO FLOW OUPUTS. TWO CONTROL SIGNAL RESPONSIVE ELECTROMAGNETIC DEVICES ARE OPERABLE TO SELECT THE FLOW OUPUT, EACH CONTROLLING FLOW RELATIVE TO A RESPECTIE OUTPUT. A SIGNAL FLOW SWITCHING ELEMENT IS MOVABLE, UNDER THE INFLUENCE OF FLUID FLOW, INTO FLOW BLOCKING RELATION IN A SELECTED ONE OF THE FLOW OUTPUTS, AND THE SWITCHING ELEMENT IS LOCKABLE IN ITS BLOCKING POSITION BY THE ASSOCIATED ELECTROMAGNETIC DEVICE. THE FLOW SWITCHING ELEMENT IS A FORKED ELEMENT, AND EITHER MAY BE PIVOTED AT THE FORK BETWEEN THE TWO OUTPUTS OR MAY BE FLEXIBLE, IN THE FORM OF A LEAF SPRING. ADJUSTMENT CANALS OR DUCTS COMMUNICATE WITH THE FLOW FEED OR SUPPLY LINE FROM OPPOSITE SIDES TO COMPENSATE FOR ASYMMETRY OF THE FLOW CONTROL ELEMENT.

p 1971 W. KRANZ suscwnouncmmrcu m.u1mc umusnucmn Filed Sept. 17, 1969mvemoa Walter Kranz Y7);%JM'77TW AT'|ORNEYS United States Patent O3,605,780 ELECTROMECHANICAL FLUIDIC TRANSDUCER Walter Kranz, Munich,Germany, assignor to Messerschmitt-Bolkow-Blohm Gesellschaft mitbeshrankter Haftung, Ottobrunn, near Munich, Germany Filed Sept. 17,1969, Ser. N0. 858,656 Claims priority, application Germany, Sept. 21,1968, P 17 74 859.3 Int. Cl. Fl5c 3/08 U.S. C]. 137-815 8 ClaimsABSTRACT OF THE DISCLOSURE An electromechanical fluidic transducer has aflow feed line communicating with two flow outputs. Two control signalresponsive electrornagnetic devices are operable to select the flowoutput, each controlling =flow relative to a respective output. A singleflow switching element is movable, under the influence of fluid flow,into flow blocking relation in a selected one of the flow outputs, andthe switching element is lockable in its blocking position by theassociated electromagnetic device. The flow switching element is aforked element, and either may be pivoted at the fork between the twooutputs 01 rnay be flexible, in the forn1 of a leaf spring. Adjustmentcanals or ducts communicate with the flow feed or supply line from opposite sides to compensate for asymmetry of the flow control element.

BACKGROUND OF THE PRIOR ART A known electromechanical fluidic transducerhas two control vanes provided in place of the control -jets of theconventional jet type fluidic transdncers. These control vanes aremounted pivotally or rotatably below the inlet port of the supply jetand, in their rest position, they rest against the Walls of the flowcham'ber. In this arrangement, the fluid or gas flow clings to one wallof the flow chamher, due to the Coanda effect. In order to redirect thisflow, the control vane on the flow side can be turned into the flow in apulse fashion by means of an externally mounted electrornagnet.

This known transducer has the drawback that the flow is switched to theother output if the output in use is blocked, or responsive to atemporary backup in the output in use. Due to the mentioned Coandaeffect, the flow continues in the new direction even if the previouslyused output again is free. Furthenmore, it is cornpletely uncertain,after an arbitrarily short interruption of the input flow, as to whichwall of the flow charnber the flow will cling that is, through whichoutput the flow Will proceed.

In another known electromechanical fluidic transducer, a fluid flow of awall jet element is switched by control currents through laterallyarranged control jets. The main flow, after being switched, forces awedge-shaped 0bstruction away from that wall along which the flowhappens to go. The obstacle 0r obstruction is provided with electricalcontacts and closes a circuit if a respective one 0f the two side Wallsof the output opening is touched by the obstruction.

Thereby, fluid signals can be converted into electrical signals with theaid of this transducer, but electrical signals cannot 'be converted intofluid-mechanical signals. This transducer is not suited for inverseoperation, as, for switching in the direction of the flow, byelectromagnetic movement of the wedgeshaped obstruction, energies cf theorder of the dynamic energy of the flowing medium are required. In suchinverted operation of this transducer, the control jets furthermorewould lose their function.

3,605,780 Patented Sept. 20, 1971 "ice SUMMARY OF THE INVENTION Thisinvention relates t0 electromechanical fluidic transducers and, moreparticularly, to a novel and improved electromechanical fluidictransducer having a flow feed or supply line and two flow outputs, andin which two electromagnetic devices are operable to select the flowoutput responsive to electrical signals.

T he objective of the invention is to provide an electromechanicalfluidic transducer which, in an economical manner, converts weakelectrical signals into strong fluidrnechanical signals, and the flowdirection of which is changed neither by a brief interruption of theinput flow nor by a brief backup in the output then in use, nor bycomplete blocking of the flow output then in use.

In accordance With the invention, an electromechanical fluidictransducer of the general type mentioned above is provided in whichthere is associated, with the electromagnetic devices, a signalswitching element which, under the influence of the flow, can be movedinto one or the other of the flow outputs, and can be locked in thisposition by the associated electromagnetic device.

In accordance with the preferred form of the invention, the switchingelement, arranged between the flow outputs of the transducer, is a forkwhich can rotate about a pivot in such a manner that its blade-shapedends extend, opposite to the direction of fluid flow, into the two flowoutputs. For maximurn lateral deflection, one Madeshaped fork end alwaysrests against the onter wall of one flow output, completely closing thisflow output, while the other blade-shaped fork end rests against theinner wall of the other flow output. Externally of the flow outputs, andnear the free ends of the fork, the electromagnets are arranged and areoperable to lock the fork.

The electromagnets operate with holding current, and are so connectedthat only one electrornagnet is energized at any one time. In theoperating condition of the transducer, the then energized electromagnetneed exert only a weak force to lock the fork end which is adjacentthereto. If the then energized electromagnet is de-energized, by anelectric input signal, and the other electromagnet is energized, thefork is rotated to the opposite side and locked in that position by theother electro magnet.

The main energy for switching of the fork is taken from the fluid flow.In addition, the field, just building up, cf the magnet then energizedacts in an accelerating sense on the fork during rotation of the latter.From this there results the advantage that the rotation of the fork setsin immediately after the switching of the electromagnets, and not onlywhen the field of the electrornagnet then energized is fully built up.If both electromagnets are deenergized, the fork oscillates by itself.

In another enrbodiment of the invention, the fork is pivotally mountedat the ve1tex of the two flow outputs.

The invention also provides for resiliently mounting, in place of thefork, a leaf spring notched a1; its free end in the shape of a fork,this leaf spring being positioned at the vertex of the flow outputs.Such a leaf spring can be mounted more simply than a rigid, pivotalfork.

In accordance with a further embodiment of the invention, adjustrnentcanals or ducts are arranged upstream from the free ends of the fork orof the leaf spring, and extend to the flow supply line frorn twoopposite sides. These adjustrnent canals serve to compensate forasymmetry of the fork or of the leaf spring, or of their mountings. Theadjustment canals furthenrnore make possible to make the switching timeto one preferred direction smaller than that to the other direction.

An object of the invention is to provide an improved electrornechanicalfluidic transducer.

Another object of the inventi-on is to provide such a tramsducer which,in an ecomomical manner, converts Weak electrical sigmals to strengfluid-mechanical signals.

A further object of the invention is to provide such a transdncer inwhich the flow direction is mot chamged either by a brief imterruption fthe input flow, a brief backup in the ontput then in use, or completebiocking of the flow output then in nse.

Another object of the imvemtion is to provide such an electrornechanicalfluidic transducer im which a single switching element iselectromagnetically locked in an adjusted position after having beenmoved to the adjusted position respomsive to fluid flow.

A further object of the invention is to provide such anelectromechanical fluidic tramsducer requiring only a very small energyfor electromagnetic locking or holding means.

For an umderstanding of the principles of the imvemtion, referemce ismade to the following descn'ption of typical embodiments thereof asillustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a sectional view of an electrornechamical fluidic transducer,embodying the imvention, and having a fork mounted between the flowontputs;

FIG. 2 is a view, similar to FIG. l, of an electromechanical fluidictransducer havimg a fork moumted at the vertex of the flow outputs;

FIG. 3 is a sectional view of amother embodiment of electromechanicalfluidic transducer, in accordance with the invemtion, and having a leafspring mounted at the vertex 0f the flow outputs; and

FIG. 4 illustrates a further embodimemt o-f the imventiom includingadjustment camals in the flow supply line.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. l, anelectromechanical fluidic transducer I imcludes a non-metallic housimg 1in which are machined or otherwise forrnecl a fluid flow supply line 2and two symmetrical flow outputs 3 and 4. Flow outputs 3 and 4 areseparated by a part of homsing 1 which forms a divider having a point orvertex in the direction toward flow supply line 2, the vertex heiligindicated at 21. Below or downstrearn of vertex 21, parts 27 and 28 ofthe immer Walls cf the respective flow outputs 3 and 4 are displaced,With respect to each other, so that shoulders 19 and 20, respectively,are provided.

A switchimg element, in the form of a symmetrical fork 5 havingblade-shaped emds 6 and 7, is mounted between flow outputs 3 and 4 forpivoting about a pivot 8-. Fork 5 is so balamced Ihat its cemter ofgravity lies at its pivot or fulcrum. The fork may cormprise aferromagnetic metal, or a material containing ferromagnetic metal.

At maximum deflection of fork 5, for exarnple to the right, blade-shapedfork end 6 closes flow ontput 3 completely. In this position, the otherfork and 7 rests against the immer wall 28 of flow output 4, belowshoulder 20, so that output 4 is completely open.

In the proximity 0-f the limits of movement of fork ends 6 and 7,respective electromagnets 9 and 10 are arranged im the outer Walls offlow outputs 3 and 4, and outside of these flow outputs. Electromagnets9 and 10, which are shown omly schematically in the drawing, eachcomprises an exciter windimg 14 and 15, respectively, and havimgrespective electrical Ieads 11, 12 and 16, 17, and respectiveelectromagnetic cores 13 and 18. Electrormagnets 9 and 10 are soconmected that they operate With holdimg current only, and also so thatonly one electromagnet 9 or 10 is emergizecl at any one tirne.

With electrornagnets 9 and 10 de-energized, the arrangement operates inthe following manmer. lf a liquid or gas flow is fed through flow supplyline 2 and fork 5 is rotated to the right, as in FIG. l, a part of thisflow jams up at the entramce to flow output 3. The flow then goesthrough flow output 4. Vortices form, im this process, a1 the shoulder20 under which rests the left blade-shaped fork and 7 at the immer Wall28 of flow output 4. These vortices ull the fork end 7 imt-o the flowoutpuc 4-. As soom as the left fork end 7 is seized by the flow, it ispressed agaimst the outer wall of flow output 4. AI the same time, rightfork emd 6 is rotated away frorn the unter wall of flow output 3 andimto engagernent with the immer Wall 27 of this flow output.

In this position of fork 5, flow jams up im front of flow output 4. 1fthe outpu*t 4 is filled With the flow medium co about the height ofvertex 21, the flow flips over to the flow output 3. Now vortices areforrned in the flow output 3 at the shoulder 19. These pull theright-hand fork end 6 into the flow output 3. As soom as this fork end 6is seized by the flow in output 3, it is pushed to the outer wall ofoutpnt 3. At the sarne time, the 1ef t-hand fork emd 7 of fork 5 isrotated away from the outer Wall cf flow Output 4 to the immer wall 28thereof. Now the flow jams up again in flow output 3 until it againflips over imto the output 4.

In the volume defined by the respective fork emds 6 and 7, therespective shoulders 19 and 20, and the respective adjoiming parts ofthe immer Walls 27 or 28, and the surrounding space, rapid pressureequalization is possible, and this prevents damping of oscillatiom of-the fork. For this pressure equalization, there can be used the spacesbetween fork 5 and the inner walls 27 and 28, as may be seen frorn FIG.1, 0r special equalization apertures may be provided.

Through the action of electrornagnets 9 and 10, the describedarramgement becornes a bistable electromechanical fluidic trandsucer.The electromagnet 9 or 10, respectively, emergized at any one tirme,has, in the operatimg comdition of the electromechanical fluidictramsducer, only to lock the fork end 6 or 7, respectively, which isadjacent 10 it, agaimst the outer wall of the respective flow outputchanmel 3 or 4.

If, for exarnple, the energized electromagmet 9 is deenergized by meansof an electric imput sigmal and the other electrornagnet 10 isenergized, right-hamd fork end 6 is no lomger locked by electrornagmet 9and fork 5 is rotated to the left up against the unter Wall of flowoutput 4. In this position, left-hamd fork end 7 is locked by theemergized electromagmet 10.

The main energy for pivoting of fork 5 is supplied, as described above,by the flow. Additionally the field, for example of the electromagnet10, Which is just bnilding up, acts on left-hamd fork end 7 in anaccelerating manner during pivotimg of fork 5.

A secomd embodimemt of an electromechanical transducer is illustrated inFIG. 2, and is desigmated With II. It difiers from tramsducer I, of FIG.l, in that fork 5 is mounted at the vertex 21 of the two flow outputs 3and 4. Electrornagnets 9 and 10 are arranged, as in FIG. l, outside theflow passages at the height of the rast positions 0f fork ends 6 and 7.Through the arrangernent cf the fork at vertex 21, the jammed-up lengthbetweem fork end 6 or 7, respectively, and flow feed line 2 isshortened. Thereby, an increase of the frequency of oscillation, andthus 0f the switching frequency of the transducer, is made possible.

FIG. 3 illustrates am electromechanical fluidic transducer III in whicha leaf spring 22, notched at its upper end to the shape of a fork, isrigidly clamped at vertex 21 of flow outputs 3 and 4 t0 serve as aswitching elememt. This embodiment cf the invention makes possible asimple mountimg of the oscillating switching element. The spring forceof the 1eaf spring switchimg element is, at the same tirne, utilized forswitching of the switching element.

If, as illustrated in FIG. 3, the flowing medium flows through flowoutput 4, the Coanda eflect occurs below the. shoulder 26, that is,below shoulder 26, the flow clings t0 the outer Wall of flow output 4.The flow will stay at this Wall if electromagnets 9 and 10 are switchedand leaf spring 22 is bent toward the left and specifically until theleft-hand fork end 7 rests against the outer Wall f flow output 4. Theembodirnent of the flow feed line 2 illustrated in FIG. 3 thereforeproduces an additional protection against leaf spring 22 swinging backdue to its own restoring force, and against the influence of the flow,before reaching the maximum lateral deflection. This form of the flowfeed line can, of course, also be applied to the embodiments of theinvention shown in FIGS. 1 and 2.

The embodiment of the invention shown at IV in FIG. 4 difiers from thetransducer II, described above, only in that adjustment canals 23 and 24are arranged upstrearn of fork 5, to the right and left, respectively,of flow feed line 2. These adjustrnent canals serve to cornpensate forasymmetries of fork or its mounting. Furthermore, they merke possible adecrease in the switching time to one preferred direction as compared tothe opposite direction. The adjnstrnent canals 23 and 24, illustrated inFIG. 4,

can, of course, also be used in the other three embodiments of theinvention, at the proper location.

While specific embodirnents of the invention have been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it Will be understood that the invention may be embodiedotherwise Without departing frorn such principles.

What is claimed ist 1. In an electromechanical fluidic transducer havinga flow feed line cornmunicating with two flow ontputs separated by adivider having a vertex, a single flow switching element oscillatablysupported at said vertex and having a free end extending toward saidflow feed line, said switching element being movable, under theinfluence of fluid flow and the diflerence in the pressures on itsopposite lateral surfaces, into flow blocking relation in a selected oneof said flow outputs; and at least one control signal responsiveelectrornagnetic device operable to select the flow output to controlflow relative to a respective output; said switching element beinglockable in its blocking position by an electrornagnetic device.

2. In an electromechanical fluidic transducer, as clairned in clairn l,adjustrnent canals cornrnunicating with opposite sides of said flow feedline and upstream from said switching element.

3. In an electromechanical fluidic transducer having a flow feed linecornrnnnicating with two flow outputs, two control signal responsiveelectrornagnetic devices operable to select the flow output, and eachoperable to control flow relative to a respective output; and a singleflow switching element movable under the influence of fluid flow intoflow blocking relation in a selected one of said flow outputs; saidswitching element being lockable in its blocking position by theassociated electromagnetic device; a fork constituting said single flowswitching element and having blade-shaped ends; said fork being mountedfor oscillation abont a pivot in a manner such that its blade-shapedends extend into the two flow outputs against the flow direction.

4. In an electromechanical fluidic transducer, as clairned in claim 3,said blade-shaped fork ends being so arranged that, at maximum lateraldeflection, one blade-shaped fork end always engages an outer wall of aflow output, closing the latter completely, While the other blade-shapedfork end engages the inner Wall of the other flow output.

5. In an electrornechanical fluidic transducer, as claimed in clairn 4,electrornagnets arranged outside the flow outputs in proximity to theflow output Wall engaging position of said fork ends, saidelectromagnets constituting said control signal responsiveelectromagnetic devices.

6. In an electromechanical fluidic transducer, as claimed in claim 5,means rotatably mounting said fork substantially at the vertex of thetwo flow outputs.

7. In an electromechanical fluidic transducer having a flow feed linecomrnunicating with two flow outputs, two control signal responsiveelectromagnetic devices operable to select the flow output, and eachoperable to control flow relative to a respective output; and a singleflow switching element movable under the influence of fluid flow intoflow blocking relation in a selected one of said flow outputs; saidswitching element being lockable in its blocking position by theassociated electrornagnetic device; a leaf spring mounted substantiallyat the vertex of said flow outputs and constituting said single flowswitching element; the free end 0f said leaf spring being notched in theshape of a fork.

8. In an electrornechanical fluidic transducer, as claimed in claim 7,said flow feed line being widened, upstream of said switching element,and symmetrically to the flow axis, by lateral displacement of its Wallsoutwardly to form shoulders.

References Cited UNITED STATES PATENTS 3l87762 6/1965 Norwood 13781.53,266,512 8/1966 Turick 13781.5 3276,463 10/1966 Bowles 13781.53,342,198 9/1967 Groeber 13781.5 3,494,369 2/1970 Inoue 13781.5X3509,775 5/1970 Evans 137815X SAMUEL SCOTT, Primary Examiner

